A Russian journalist has been brutally beaten, according to Russian media, in the second such attack in days.

Anatoliy Adamchuk, from the Zhukovskiye Vesti suburban Moscow weekly, suffered concussion and head injuries, according to Ekho Moskvy news agency.

It comes after leading journalist Oleg Kashin was severely beaten outside his home on Saturday.

Russian President Dmitry Medvedev has called for his attackers to be found and punished.

Footage of what appears to be Mr Kashin's assault has spread online and was aired on state TV.

The incidents have increased pressure on the Kremlin to investigate cases of press violence, which are common in Russia.

Whoever is involved in this crime will be punished regardless of his position, place in society or accomplishmentsDmitry Medvedev, Russian President

Mr Adamchuk had been reporting on the arrests of children protesting against the cutting down of a forest as part of the construction of a road.

"Two unidentified individuals attacked him from behind, striking him on the back of his head and delivering several more blows when he was already down on the ground," journalist Sergey Grammatin, a colleague of Mr Adamchuk, was quoted as saying.

Mr Kashin had also been reporting on demonstrations against the building of a road through a forest, a key motorway project that has now been put on hold by the government.

An environmental activist who had campaigned against the motorway was brutally attacked in the town of Khimki on Thursday.

Konstantin Fetisov's skull was fractured shortly after he was released by police who had questioned him about a protest.

'More blows'

Meanwhile, a 90-second clip of what purported to show the attack on Mr Kashin, a reporter with Kommersant business daily, showed the extent of the assault.

The blows were so brutal. It's incomprehensible. I hope he will survive. I believe itVladimir Kashin, Victim's father

In the black and white film, two figures are seen striking Mr Kashin up to 50 times with an iron bar or similar weapon.

Mr Kashin, who was attacked outside his Moscow apartment building in the early hours of Saturday, suffered a fractured jaw, broken shins and injuries to his fingers and skull.

President Dmitry Medvedev has ordered an investigation into the assault, which police are treating as attempted murder.

"There are forces which believe that by using such methods they can shut anybody up, whether it's a journalist or a politician," he said.

"Whoever is involved in this crime will be punished regardless of his position, place in society or accomplishments."

Kremlin challenge

Oleg Kashin's father, Vladimir, said that the attack was a potent challenge to the authorities because it took place 10 minutes' walk from the Kremlin.

"The blows were so brutal. It's incomprehensible. I hope he will survive. I believe it," he said.

A group of leading Russian journalists has written an open letter to President Medvedev to make journalists' safety a priority.

It added that that eight Russian reporters had been killed this year and another 40 had come under attack.

Human rights groups say there have been 19 unsolved murders of journalists since 2000 and that investigations into attacks lead nowhere.

The Organisation for Security and Co-operation in Europe urged the authorities to "finally turn their declarations into real action".